Hi .... was wondering if anyone could give me any advise on my grandmeister deluxe 40....one of my tubes had blown, so I decided to replace all tubes with new JJ electronic vacuum tubes.... After replacing them everything powers up..... tubes seem to power up, but on back panel the TSC lights all stay on!... which I take means No current... After reading Manuel it seems because my tube had blown it might have blown the anode fuse T400mA 250V fuse...which is giving me know current... can anyone tell me where to find this fuse to check it as I can't see it anywhere? do I need to remove more than just the outer casing?
Hi there. Hats off to you Ju99ler for doing your own research before coming here! You try, you learn, you know next time.
The anode fuse is inside the unit on the main PCB. You only need to remove the bottom panel to access it. Yoiu may even be able to see it through the base vents. As it involves the HT (read *lethal*) it is usually best to keep it out of sight for day to day use which is why it is not on the back panel. Now, having reminded you of the dangers of messing about with HT, this is very safe if you just follow three pieces of safety info. 1) Remove the plug from the wall socket before any work commences. 2) Wait at least 5 minutes after turning the amp off before touching anything inside. 3) Only ever replace with the exact same specification of fuse, absolutely no "temporary" fixes - EVER!
Remove the bottom screws and the panel should come off. The HT fuse is pretty obvious. It is labelled FU1 and should be T400mAL/250V. I have attached a diagram of what you are looking for. The fuse is a time delay (slow blow) 400milliamp fuse, nothing else will do! They are 20mm size. Get a small stock of them before you open the amp up, it's always wise to have a few on hand. As long as you leave the time I said the voltage inside will have dropped down to close to 0V. The H&K amps have drain resistors across their power lines to do that one task. Removing the fuse is simple as long as you are careful and don't have 4 thumbs and one finger. You can lever it out with something slim, just don't be too forceful, you shouldn't need to be.
Remember, fuses can look fine and still be blown inside the end caps. The only real way to check them is to use a meter for continuity and even that can be caught out. It's simpler just to change them out with a known good one and then test. Be sure to come back and let us know how you got on. Good luck.
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The information you sent me is very much appreciated...After changing the tubes I was looking for fuse up top in and around tubes.... Didn't think about taking the bottom off..oh well lesson learnt... So this morning I have removed the bottom and found the fuse it has blown, all black under one end.... I have ordered some new fuses T400mAL/250V and hopefully will be here tomorrow... Fingers crossed that this sorts my problem... will post the outcome once fuse is changed